Patent 3542199 (Reverse Osmosis Water Purification Unit)

A reverse osmosis water purification unit has a casing containing a semipermeable membrane cartridge with its brine flow control in the form of a pair of connected restricted conduits. Preferably feed water passes through an annular filter surrounding the cartridge before entering one end of the cartridge. Product water is collected in a central tube in the cartridge and is passed through purifying material before being withdrawn from the casing outlet. A product water storage tank may be connected to the product water purifying system so that water drawn from this tank or directly from the product water collector passes through the purifying material before reaching the casing outlet. A connection through a relief valve from the product water collector to the connection between the brine flow control conduits controls pressure in the purified water system.